Martínez Martínez V, López Arbeloa F, Bañuelos Prieto J, Arbeloa López T, López Arbeloa I
Departamento de Química Física, Universidad País Vasco-EHU, Apartado 644, 48080-Bilbao, Spain.
Langmuir. 2004 Jul 6;20(14):5709-17. doi: 10.1021/la049675w.
The morphology of thin films of Laponite (Lap) clay elaborated by the evaporation method and spin-coating technique was analyzed by atomic force microscopy and scanning electron microscopy, indicating a better quality film for the latter procedure. Rhodamine 6G (R6G) laser dye was intercalated into these films by ion exchange mechanism, performed by immersing the clay film into adequate dye solutions in which the effect of the dye concentration, immersion time, and nature of the solvent on the adsorption process were checked. The adsorption of R6G at the interlayer space of Lap was analyzed by the X-ray diffraction technique, and the presence of several R6G species (monomers and aggregates) was characterized by absorption and fluorescence spectroscopies. Less viscous solvents lead to higher dye loadings, suggesting a diffusional process for the intercalation of the dye in the interlayer spaces of Lap, and polar solvents favor the swellability of the interlayer space giving rise to a more homogeneous distribution of R6G molecules through the film and decreasing the dye aggregation. With the aging of the samples, the dye molecules can migrate through the interlayer spaces, leading to a more expanded distribution of R6G molecules and to the dye deaggregation.
通过原子力显微镜和扫描电子显微镜对采用蒸发法和旋涂技术制备的锂皂石（Lap）粘土薄膜的形态进行了分析，结果表明后一种方法制备的薄膜质量更好。通过离子交换机制将罗丹明6G（R6G）激光染料插入这些薄膜中，具体做法是将粘土薄膜浸入适当的染料溶液中，并考察染料浓度、浸泡时间和溶剂性质对吸附过程的影响。采用X射线衍射技术分析了R6G在Lap层间空间的吸附情况，并通过吸收光谱和荧光光谱对几种R6G物种（单体和聚集体）的存在进行了表征。粘度较小的溶剂会导致更高的染料负载量，这表明染料在Lap层间空间的插层过程是一个扩散过程，极性溶剂有利于层间空间的膨胀，使R6G分子在整个薄膜中分布更均匀，并减少染料聚集。随着样品的老化，染料分子可以在层间空间迁移，导致R6G分子分布更分散，染料解聚。
